Jean-Claude Trigeassou

Diagnosis by parameter estimation of stator and rotor faults occurring in induction machines

In this paper, the authors give a new model of squirrel-cage induction motors under stator and rotor faults. First, they study an original model that takes into account the effects of interturn faults resulting in the shorting of one or more circuits of stator-phase winding. They introduce, thus, additional parameters to explain the fault in the three stator phases. Then, they propose a new faulty model dedicated to broken rotor bars detection. The corresponding diagnosis procedure based on parameter estimation of the stator and rotor faulty model is proposed. The estimation technique is performed by taking into account prior information available on the safe system operating in nominal conditions. A special three-phase induction machine has been designed and constructed in order to simulate true faulty experiments. Experimental test results show good agreement and demonstrate the possibility of detection and localization of previous failures.

A method for modelling and simulation of fractional systems

An original method for modelling and simulation of fractional systems is presented in this article. The basic idea is to model the fractional system by a state-space representation, where conventional integration is replaced by fractional one with the help of non-integer integrator. This operator is itself approximated by a N dimensional system composed of an integrator and of a phase-lead filter. This method is compared to other techniques like direct discretization of the fractional derivator and diffusive representation. Numerical simulations exhibit the general applicability and flexibility of this new approach to different types of fractional models and to non-conventional non-integer derivation with limited spectral range.

Approximation and identification of diffusive interfaces by fractional models

Heat transfer problems obey to diffusion phenomenon. In this paper we show that they can be modelled with the help of fractional systems. The simulation is based on a fractional integrator operator where the non-integer behaviour acts only over a limited spectral band. Starting with frequency considerations derived from the analysis of a diffusion problem, a more general approximation of the fractional system is proposed. A state-space model is presented that gives an accurate simulation for transients, and with which it is possible to carry out an output-error technique to estimate the model parameters. Numerical simulations of the heat transfer problem are used to illustrate the improvements of the proposed model.

Parameter Estimation of Fractional Systems: Application to the Modeling of a Lead-Acid Battery

Abstract Black box modeling of diffusion processes can be performed by fractional systems. The simulation of these particular systems is based on a new fractional integrator, with limited spectral range for non integer order. Parameter estimation of this class of systems is performed by an OE identification technique. This paper presents the application of this new methodology to the modeling of the dynamics of a lead-acid battery.

Parameter estimation of fractional models : Application to the modeling of diffusive systems

Abstract Black box modeling of diffusion processes can be performed by fractional models. The simulation of these particular models is based on a new fractional integrator, with limited spectral range. Parameter estimation of this class of systems is performed by an OE identification technique. This paper presents the application of this new methodology to the modeling of different diffusive systems dealing with electrochemistry, heat transfer and electromagnetism.

Fractional Modelling and Identification of a Thermal Process

Heat transfer problems are subject to diffusion phenomenon, and can be modelled with the help of fractional systems. The simulation of these particular systems is based on a fractional integrator, where the non-integer behaviour occurs only within a limited spectral band. A first model, based on the use of one fractional integrator, has been already defined and tested on a thermal pilot. Starting from frequency considerations derived from the analysis of a diffusion problem, a more general approximation of the fractional system is proposed here. The new model is based on the use of two fractional integrator operators. This makes it possible to define a state-space model for simulation of transients, and to use an output-error technique in order to estimate the parameters of the model. Experimental results obtained for a thermal process illustrate the improvements obtained using the proposed model.

MODELLING AND SIMULATION OF FRACTIONAL SYSTEMS USING A NON INTEGER INTEGRATOR

An original method for modelling and simulation of fractional systems is presented in this paper. The basic idea is to model the fractional system by a state-space representation, where conventional integration is replaced by a fractional one with the help of a non integer integrator. This operator is itself approximated by a N + 1 dimensional system composed of an integrator and of a phase-lead filter. This method is compared to other techniques like direct discretization of the fractional derivator and diffusive representation. Numerical simulations exhibit the general applicability and flexibility of this new approach to different types of fractional models and to non conventional non integer derivation with limited spectral range.

Frequency Identification by Non Integer Model

Abstract This article deals with frequency identification by non integer model. The problem consists in interpolating a frequency response of system using implicit generalized derivative transmittance. The solution of this problem is given by two strategies, one linear and the other nonlinear. Linear approach determines the parameters of model by the minimization of a criterion based on the prediction error of intermediate integer model. Nonlinear approoch determines directly parameters from the minimization of a criterion using the gradient mcthod. Two applications illustrate these two different approachs.

Approximation and Identification of Fractional Systems

Heat transfer problems obey to diffusion phenomenon. They can be modelled with the help of fractional systems. The simulation of these particular systems is based on a fractional integrator where the non integer behaviour acts only on a limited spectral band. Starting from frequential considerations, a more general approximation of the fractional system is proposed in this communication. It makes it possible to define a state-space model for simulation of transients, and to carry out an output-error technique in order to estimate the parameters of the model. A real application on a thermal system is presented to illustrate the advantages of the proposed model.Copyright

Restricted-Complexity Controller with Crone Control-System Design and Closed-Loop Tuning

The benchmark problem, “Design and optimisation of restricted complexity controllers”, for an active suspension system is studied. An initial fractional controller based on the first and third generation Crone methodologies is designed first. The high-level parameters of the rational controller are then fine-tuned using a tuned in closed-loop approach. The optimisation technique uses the power spectral density of the closedloop simulation of the residual force to be minimised. This final controller is finally assessed with real-time implementation.